Answer:
D
Step-by-step explanation:
(a) 4
(b) y = sqrt(9 - (9/16)x^2)
The best guess to the formula using knowledge of the general formula for an ellipse is:
x^2/16 + y^2/9 = 1
(a). An ellipse is reflectively symmetrical across both the major and minor axis. So if you can get the area of the ellipse in a quadrant, then multiplying that area by 4 would give the total area of the ellipse. So the factor of 4 is correct.
(b). The general equation for an ellipse is not suitable for a general function since it returns 2 y values for every x value. But if we restrict ourselves to just the positive value of a square root, that problem is easy to solve. So let's do so:
x^2/16 + y^2/9 = 1
x^2/16 + y^2/9 - 1 = 0
x^2/16 - 1 = - y^2/9
-(9/16)x^2 + 9 = y^2
9 - (9/16)x^2 = y^2
sqrt(9 - (9/16)x^2) = y
y = sqrt(9 - (9/16)x^2)
Simply substitute the value of
3
given. In other words,
f
(
3
)
is the function of
f
(
x
)
, however, in this case,
x
is
3
f
(
3
)
=
3
(
3
)
−
4
Distribute
3
through the parenthesis
f
(
3
)
=
9
−
4
Simplify
f
(
3
)
=
5
Median is a middle value
So it is 28
